1. Field of the Invention
The present invention relates to a household hand-operated device for measuring, dispensing and storing of powder, granular and grain materials such as instant and ground coffee, baby formula, dried milk, non-dairy creamer, sugar, flour, detergents, coffee beans, rice, buckwheat and the like. More particularly, it relates to a device for measuring, dispensing and storing of a predetermined volume of powder, granular and grain materials, from a special container or from a container in which the materials are sold or stored.
2. Background of the Invention
Various types of devices, combining storing and (or—only) measuring and dispensing functions for powder and granular materials have been developed in the past. Examples include U.S. Pat. No. 1,433,970 to Resek; U.S. Pat. No. 1,471,621 to McCord; U.S. Pat. No. 1,904,736 to Wooster; U.S. Pat. No. 3,072,299 to Sessions et al.; U.S. Pat. No. 3,183,190 to Crawford; U.S. Pat. No. 3,193,139 to Swindler, U.S. Pat. No. 3,421,491 to Tuvim et al.; U.S. Pat. No. 6,430,371 B1 to Sherman at al.
Most of the prior art devices for storing, measuring and dispensing powder and granular materials have some or all of the following drawbacks:                necessity to pour powder and granular materials to be dispensed from a container in which these materials are normally sold into a special container;        complexity of dismantling and reassembling of the device for washing and cleaning;        inconvenience in operation, especially for elderly and handicapped people.        
These drawbacks were avoided in the device described in the U.S. Pat. No. 5,421,491, however even this device, as well as all others in the prior art, does not actually provide airtight conditions for storing the materials. As a result, humidity inside the container is uncontrollable, sometimes during several weeks or even more of storage. If the humidity is high, hygroscopic materials such as instant coffee, flour, sugar, salt, etc. stored in the container, become caked and quickly deteriorate. In the case of a coffee dispenser, coffee freshness steadily declines during its storage and dispensing because of losing aroma, even at low air humidity. This drawback is especially serious for areas of high humidity climate where the prior art devices are completely impractical.
Another drawback of the device described in the U.S. Pat. No. 5,421,491, as well as other earlier developed structures based on hand-operated plunger-type dispensers, is that placing a container with attached dispensing device requires additional space on a shelf or a kitchen table. This drawback is caused by a slide extended from the device's contour. The extended slide also undesirably affects the esthetic characteristics of the device.
A further step in the improvement of dispensing devices was made in the U.S. Pat. No. 6,450,371 B1. The described dispenser provides airtight conditions for stored materials while providing for measured dispensing of the materials; the device is compact, has monolith-like shape during storage of the material, and it is esthetically better than the dispensers of the prior art design.
However, even this device can be further improved. In the case of dispensing of materials, including sticky particles, consistency of the material measured flowing out of the dispenser is not provided by the prior art device. This happens because the sticky particles form a dome-shaped bridge above an input opening in the dispenser's slide that leads to unstable filling of the opening. As a result, the amount of the dispensed material can be quite different from that desired. This limits the field of application of the device to materials consisting of non-sticky particles or requires shaking the device before each working stroke and that is inconvenient.
Another drawback of the device, is usage of a compression spring as a mechanism for motion of the device's slide from its discharging position to filling position. Providing lateral stability of the compression spring determines the minimal diameter of the spring, and thus the minimal height of the slide. In many cases it increases the height of the device. Position of the spring between the slide and the housing also increases the size of the device.
Still another drawback of the device is its inability to measure and dispense grain materials, such as coffee beans, rice, buckwheat, etc. When the slide filled with the material is moved toward discharging opening, one or several grains can take a position partially outside the slide's counter that block movement of the slide toward its discharging position. This significantly narrows the field of application of the devices designed according to U.S. Pat. No. 6,450,371 B1.
The main objects of the present invention are to overcome the above drawbacks of the prior art devices, i.e.:                To prevent formation of bridge formed by sticky particles of the dispensed materials above an input opening in a slide of the dispenser.        To use for backward motion of a slide of the device the means that does not lose lateral stability under the applied loads.        To develop a device that can be used for dispensing not only powder and granular materials, but grain materials also.        
Other objects of the invention, as well as particular features, elements and advantages thereof, will be elucidated in, or be apparent from, the following description and the accompanying drawing figures.